Juan Padilla has sold ice pops from a cart he pushes around Oakland's Lake Merritt for years. He's never seen the lake like this.

"Lots of people, lots of popsicles," he said during a recent golden evening at the lake. Joggers with white earbuds and spandex sprinted by while young women sipped wine from paper cups on a blanket near a pile of bicycles. A man stopped to buy two popsicles, handing a crisp $20 to Padilla.

"Everyone is here now," said Padilla, a Fruitvale neighborhood resident who said he earned almost twice as much this summer as he did last year selling treats at the lake.

The boom around Lake Merritt is due both to the city's multimillion-dollar cleanup of the 155-acre lake and an influx of San Francisco refugees.

"In the last 18 to 24 months we've seen an influx of 20- to 35-year-olds who are moving from San Francisco because they are getting pushed out because their rents are too high," said Brandon Geraldo, a vice president at the real estate company Colliers International who specializes in Oakland's rental market. "Lake Merritt is really the driver for them."

Oakland invested nearly $200 million since 2002 into rehabilitating the lake, once a stinky, swamp pond filled with trash, bacteria and sewage. The lake is cleaner than it has been in decades and a project to connect Lake Merritt to the bay should finish early next year.

Lights twinkle around the edge of the lake at dusk, and the fog that often blankets much of San Francisco in the summer rarely reaches into Oakland. Large, elegant apartments surround the lake, and young couples and families picnic and play on its shores in greater numbers than anyone can remember.

Every few weeks, a new restaurant or bar opens along Lakeshore or Grand avenues. Crime is down. Rents are up. Way up.

Big jump in rents

The average rent around Lake Merritt has risen 53 percent since 2011 to $2,398 - a larger increase than in any other neighborhood in the city, according to real estate data. The average rent in San Francisco, in comparison, is $3,229.

The changes are welcome by some longtime Oaklanders, but upsetting to others.

"This is bigger and beyond what anyone expected and it just keeps growing," said Tora Rocha, a city parks supervisor who oversees Lake Merritt. "The energy level is like nothing I have ever seen and I have been here 34 years."

But some longtime residents in rent-controlled units said they're feeling increasingly pressured by landlords to move out and make room for younger, more affluent tenants.

In the past three years, more than 200 restaurants have opened in Oakland, according to city data.

"As you start to have higher income, more affluent people come into a particular neighborhood, they're going to have certain amenities that they want - restaurants, coffee shops," said Malo Hutson, an assistant professor of city and regional planning at UC Berkeley who has studied gentrification in Oakland.

'This is like my front yard'

Crime has also fallen around the lake, said Oakland Police Capt. Rick Orozco, who oversees the Lake Merritt area.

"It used to be on weekends and even calm nights I used to get complaints about loitering and drug sales," Orozco said. "Now, in the last few months, I get calls about loud music and barbecues. It is a great problem."

Robberies in Orozco's police district, which extends into the Fruitvale neighborhood, have fallen by 35 percent since this time last year and shootings have dropped by 32 percent.

Jen Butler, 32, who moved with her husband from San Francisco to an apartment in the Adams Point neighborhood near the lake earlier this year, said she was drawn to Lake Merritt because it offered something she couldn't find in other parts of the city.

"This is like my front yard, this is so cool," she said as she sat on a bench near the shore of the lake. "San Francisco was fun but it got expensive. It wasn't like this there."

The changes are spreading to the east side of the lake, Geraldo said, which, until recently, was more commonly associated with seedy motels, sex workers and garbage.

"East Lake, it has really transitioned over the last three years," Geraldo said. "Investors are hot and heavy to acquire property there because you're getting spillover from Adams Point."

Downside of the boom

But that worries Robbie Clark, an organizer with Causa Justa, an Oakland housing advocacy group, who grew up in Oakland and had to move out of the East Lake area after eight years because he couldn't find affordable apartments.

"You see a lot of things around the lake that are catering to folks that are coming in and not so much to the existing or long-term residents," said Clark, 33. "Those profits come at the expense of existing and long-term residents."

Clark said that while he doesn't track evictions or unfair rent increases around Lake Merritt, he was aware of at least three buildings in the area where new owners are trying to squeeze out long-term tenants so they can raise rents.

"It puts a lot of pressure on that area," Clark said.

Councilwoman Pat Kernighan, whose district includes much of Lake Merritt, said that while she was concerned about rising rents, she recognized that Lake Merritt was booming.

"I love their energy and ability to support our local businesses," Kernighan said. "But the increased demand for a finite supply of apartments is driving up rents for everyone. That doesn't mean we should discourage people from coming to Oakland, but rather that we need to build more housing."